A hand-made air GM counter was developed using simple, low-cost and easily available materials. The detector was successful in demonstrating the inverse square law, shielding effect, and determining the half-life of thoron gas. The possibility of using the tube design as a simple proportional counter to provide energy information has been explored and preliminary experiment and simulation results appear to agree at low energy. The energy deposition characteristics for an internally placed alpha-emitting Rn-220 were simulated using Particle and Heavy Ion Transport code System (PHITS).